U.S. patent application number 15/533829 was filed with the patent office on 2017-11-16 for method of protecting an article having a complex shape.
The applicant listed for this patent is General Electric Company. Invention is credited to Mamatha NAGESH, Bala Srinivasan PARTHASARATHY, Gopi Chandran RAMACHANDRAN, Atanu SAHA, Shalini THIMMEGOWDA.
Application Number | 20170326587 15/533829 |
Document ID | / |
Family ID | 55070133 |
Filed Date | 2017-11-16 |
United States Patent
Application |
20170326587 |
Kind Code |
A1 |
SAHA; Atanu ; et
al. |
November 16, 2017 |
METHOD OF PROTECTING AN ARTICLE HAVING A COMPLEX SHAPE
Abstract
A silicone bond coat composition having a viscosity of less than
1,600 centistokes is applied to substantially all external surfaces
of the article and then cured. A liquid silicone elastomer outer
coat composition comprising a high viscosity first liquid silicone
elastomer formulation and a low viscosity second liquid silicone
elastomer formulation is then applied and cured to provide a
protected article having a complex shape. Optimal coatings result
from a careful balancing of component viscosities. In an
embodiment, the first formulation has a viscosity greater than
300,000 centistokes, and the second formulation has a viscosity
less than 6,000 centistokes, and the liquid silicone elastomer
outer coat composition comprises from about 60 to about 40 percent
by weight of the first formulation and from about 40 to about 60
percent by weight of the second liquid silicone elastomer
formulation.
Inventors: |
SAHA; Atanu; (Bangalore,
IN) ; RAMACHANDRAN; Gopi Chandran; (Bangalore,
IN) ; NAGESH; Mamatha; (Bangalore, IN) ;
THIMMEGOWDA; Shalini; (Bangalore, IN) ;
PARTHASARATHY; Bala Srinivasan; (Bangalore, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
General Electric Company |
Schenectady |
NY |
US |
|
|
Family ID: |
55070133 |
Appl. No.: |
15/533829 |
Filed: |
December 1, 2015 |
PCT Filed: |
December 1, 2015 |
PCT NO: |
PCT/US2015/063115 |
371 Date: |
June 7, 2017 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B32B 2250/02 20130101;
B32B 2250/248 20130101; C08G 77/20 20130101; B05D 1/02 20130101;
C09D 183/04 20130101; C08L 83/00 20130101; F04D 29/403 20130101;
B05D 2202/00 20130101; F05D 2300/611 20130101; C08L 83/00 20130101;
C08L 83/00 20130101; F05D 2300/437 20130101; B63H 5/165 20130101;
F04D 29/4206 20130101; B05D 7/14 20130101; C09D 183/04 20130101;
B05D 7/546 20130101; F04D 29/043 20130101; F04D 29/053 20130101;
F04D 29/522 20130101; B05D 1/18 20130101; F04D 17/00 20130101; B32B
25/20 20130101; F04D 7/04 20130101; B32B 2383/00 20130101; C08G
77/12 20130101 |
International
Class: |
B05D 7/00 20060101
B05D007/00; B05D 7/14 20060101 B05D007/14; B05D 1/02 20060101
B05D001/02; C09D 183/04 20060101 C09D183/04; B05D 1/18 20060101
B05D001/18 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 8, 2014 |
IN |
6188/CHE/2014 |
Claims
1. A method of protecting an article having a complex shape, the
method comprising: applying a silicone bond coat composition to
substantially all external surfaces of a first article having a
complex shape, the silicone bond coat composition having a
viscosity of less than 1,600 centistokes; curing the silicone bond
coat composition in contact with the external surfaces of the first
article to provide a first intermediate article; applying a liquid
silicone elastomer outer coat composition comprising a high
viscosity first liquid silicone elastomer formulation and a low
viscosity second liquid silicone elastomer formulation to
substantially all external surfaces of the first intermediate
article to provide a second intermediate article, wherein the high
viscosity first liquid silicone elastomer formulation has a
viscosity greater than 300,000 centistokes, wherein the low
viscosity second liquid silicone elastomer formulation has a
viscosity less than 6,000 centistokes; and curing the liquid
silicone elastomer outer coat in contact with the external surfaces
of the second intermediate article to provide a protected article
having a complex shape, wherein the liquid silicone elastomer outer
coat composition comprises from about 60 to about 40 percent by
weight of the high viscosity first liquid silicone elastomer
formulation and from about 40 to about 60 percent by weight of the
low viscosity second liquid silicone elastomer formulation.
2. The method according to claim 1, wherein the article having a
complex shape is selected from the group consisting of centrifugal
compressors stator casings; gas turbine compressor casings; slurry
pump impellers; surface pump components; marine impellers, and
drive shafts.
3. The method according to claim 1, wherein the first article
having a complex shape is a compressor component.
4. The method according to claim 1, wherein the first article
having a complex shape is an impeller.
5. The method according to claim 1, wherein the first article
having a complex shape comprises one or more surfaces comprising
mild steel, aluminum, copper, and alloys of the foregoing.
6. The method according to claim 1, wherein curing the silicone
bond coat composition in contact with the external surfaces to
provide a first intermediate article comprises heating to a
temperature in a range from about 80 to about 150 degrees
centigrade.
7. The method according to claim 1, wherein curing the liquid
silicone elastomer outer coat composition in contact with the
external surfaces of the second intermediate article to provide a
protected article having a complex shape comprises heating to a
temperature in a range from about 180 to about 250 degrees
centigrade.
8. The method according to claim 1, wherein the liquid silicone
elastomer outer coat composition comprises a filler in an amount
corresponding to from about 1 to about 20 percent of a total volume
of the outer coat composition.
9. The method according to claim 7, wherein the filler is
characterized by a maximum particle size in a range from about 2
nanometers to about 10 microns.
10. The method according to claim 1, wherein a cured bond coat has
a thickness in a range from about 5 to about 20 microns and a cured
outer coat has a thickness in a range from about 50 to about 500
microns.
11. The method according to claim 1, wherein a cured bond coat has
a surface roughness in a range from about 0.5 to about 1 microns
and a cured outer coat has a surface roughness in a range from
about 0.5 to about 3 microns.
12. The method according to claim 1 further comprising a step of
cleaning the first article having a complex shape with an organic
solvent.
13. The method according to claim 1, wherein the bond coat
composition is applied via a spray coating technique.
14. The method according to claim 1, wherein the bond coat
composition is applied via a dip coating technique.
15. The method according to claim 1, wherein the liquid silicone
elastomer outer coat composition is applied via a spray coating
technique.
16. The method according to claim 1, wherein the liquid silicone
elastomer outer coat composition is applied via a dip coating
technique.
17. A method of protecting an article having a complex shape, the
method comprising: applying a silicone bond coat composition to
substantially all external surfaces of a first article having a
complex shape, the silicone bond coat composition having a
viscosity of less than 1,600 centistokes; curing the silicone bond
coat composition in contact with the external surfaces of the first
article at a temperature in a range from about 80 to about 150
degrees centigrade to provide a first intermediate article;
applying a liquid silicone elastomer outer coat composition
comprising a first liquid silicone elastomer formulation having a
viscosity greater than 300,000 centistokes and a second liquid
silicone elastomer formulation having a viscosity less than 6,000
centistokes to substantially all external surfaces of the first
intermediate article to provide a second intermediate article; and
curing the liquid silicone elastomer outer coat composition in
contact with the external surfaces of the second intermediate
article at a temperature in a range from about 180 to about 250
degrees centigrade to provide a protected article having a complex
shape; wherein the liquid silicone elastomer outer coat composition
comprises from about 60 to about 40 percent by weight of the first
liquid silicone elastomer formulation and from about 40 to about 60
percent by weight of the second liquid silicone elastomer
formulation.
18. The method according to claim 16, wherein the liquid silicone
elastomer outer coat composition comprises about 20 by volume of a
filler based on a total volume of the liquid silicone elastomer
outer coat composition.
19. The method according to claim 17, wherein the filler comprises
one or more of Al.sub.2O.sub.3, graphite, SiO.sub.2, SiC,
Si.sub.3N.sub.4, SiCN, WC, and ZrO.sub.2.
20. A method of protecting an article having a complex shape, the
method comprising: applying via a dip coating technique a silicone
bond coat composition to substantially all external surfaces of a
first article having a complex shape, the silicone bond coat
composition having a viscosity of less than 1,600 centistokes;
curing the silicone bond coat composition in contact with the
external surfaces of the first article at a temperature in a range
from about 80 to about 150 degrees centigrade to provide a first
intermediate article; applying via a dip coating technique a liquid
silicone elastomer outer coat composition comprising a first liquid
silicone elastomer formulation having a viscosity greater than
300,000 centistokes and a second liquid silicone elastomer
formulation having a viscosity less than 6,000 centistokes to
substantially all external surfaces of the first intermediate
article to provide a second intermediate article; and curing the
liquid silicone elastomer outer coat composition in contact with
the external surfaces of the second intermediate article at a
temperature in a range from about 180 to about 250 degrees
centigrade to provide a protected article having a complex shape;
wherein the liquid silicone elastomer outer coat composition
comprises from about 60 to about 40 percent by weight of the first
liquid silicone elastomer formulation and from about 40 to about 60
percent by weight of the second liquid silicone elastomer
formulation and wherein one or more of the first liquid silicone
elastomer formulation and the second liquid silicone elastomer
formulation comprises one or more fillers in an amount such that
the total amount of filler in the liquid silicone elastomer outer
coat composition corresponds to from about 10 to about 30 percent
by volume of a total volume of the liquid silicone elastomer outer
coat composition.
21. The method according to claim 19, wherein the first article
having a complex shape is an impeller comprising mild steel.
Description
BACKGROUND
[0001] The present invention provides a method of protecting an
article having a complex shape. In particular, the present
invention provides a method of protecting articles comprising
non-line-of-sight-surfaces requiring protection from the
environment.
[0002] While a large number of non-line-of-sight compatible coating
techniques such as Chemical Vapor Deposition and Electroless Nickel
Plating are available for the protection of surfaces within complex
structures, such techniques are inapplicable for use with polymeric
organic coatings which must rely on the use of non-productive
diluents to provide formulations suitable for use in
non-line-of-sight compatible coating techniques.
[0003] While much ingenuity has gone into the development of state
of the art polymer coating technologies, further enhancements are
needed as equipment requiring some level of additional protection
is deployed in progressively harsher environments.
BRIEF DESCRIPTION
[0004] In one embodiment, the present invention provides a method
of protecting an article having a complex shape, the method
comprising: (a) applying a silicone bond coat composition to
substantially all external surfaces of a first article having a
complex shape, the silicone bond coat composition having a
viscosity of less than 1,600 centistokes; (b) curing the silicone
bond coat composition in contact with the external surfaces of the
first article to provide a first intermediate article; (c) applying
a liquid silicone elastomer outer coat composition comprising a
high viscosity first liquid silicone elastomer formulation and a
low viscosity second liquid silicone elastomer formulation to
substantially all external surfaces of the first intermediate
article to provide a second intermediate article; and (d) curing
the liquid silicone elastomer outer coat in contact with the
external surfaces of the second intermediate article to provide a
protected article having a complex shape; wherein the high
viscosity first liquid silicone elastomer formulation has a
viscosity greater than 300,000 centistokes, wherein the low
viscosity second liquid silicone elastomer formulation has a
viscosity less than 6,000 centistokes, and wherein the liquid
silicone elastomer outer coat composition comprises from about 60
to about 40 percent by weight of the high viscosity first liquid
silicone elastomer formulation and from about 40 to about 60
percent by weight of the low viscosity second liquid silicone
elastomer formulation.
[0005] In an alternate embodiment, the present invention provides a
method of protecting an article having a complex shape, the method
comprising: (a) applying a silicone bond coat composition to
substantially all external surfaces of a first article having a
complex shape, the silicone bond coat composition having a
viscosity of less than 1,600 centistokes; (b) curing the silicone
bond coat composition in contact with the external surfaces of the
first article at a temperature in a range from about 80 to about
150 degrees centigrade to provide a first intermediate article; (c)
applying a liquid silicone elastomer outer coat composition
comprising a first liquid silicone elastomer formulation having a
viscosity greater than 300,000 centistokes and a second liquid
silicone elastomer formulation having a viscosity less than 6,000
centistokes to substantially all external surfaces of the first
intermediate article to provide a second intermediate article; and
(d) curing the liquid silicone elastomer outer coat composition in
contact with the external surfaces of the second intermediate
article at a temperature in a range from about 180 to about 250
degrees centigrade to provide a protected article having a complex
shape; wherein the liquid silicone elastomer outer coat composition
comprises from about 60 to about 40 percent by weight of the first
liquid silicone elastomer formulation and from about 40 to about 60
percent by weight of the second liquid silicone elastomer
formulation.
[0006] In yet another embodiment, the present invention provides a
method of protecting an article having a complex shape, the method
comprising: (a) applying via a dip coating technique a silicone
bond coat composition to substantially all external surfaces of a
first article having a complex shape, the silicone bond coat
composition having a viscosity of less than 1,600 centistokes; (b)
curing the silicone bond coat composition in contact with the
external surfaces of the first article at a temperature in a range
from about 80 to about 150 degrees centigrade to provide a first
intermediate article; (c) applying via a dip coating technique a
liquid silicone elastomer outer coat composition comprising a first
liquid silicone elastomer formulation having a viscosity greater
than 300,000 centistokes and a second liquid silicone elastomer
formulation having a viscosity less than 6,000 centistokes to
substantially all external surfaces of the first intermediate
article to provide a second intermediate article; and (d) curing
the liquid silicone elastomer outer coat composition in contact
with the external surfaces of the second intermediate article at a
temperature in a range from about 180 to about 250 degrees
centigrade to provide a protected article having a complex shape;
wherein the liquid silicone elastomer outer coat composition
comprises from about 60 to about 40 percent by weight of the first
liquid silicone elastomer formulation and from about 40 to about 60
percent by weight of the second liquid silicone elastomer
formulation and wherein one or more of the first liquid silicone
elastomer formulation and the second liquid silicone elastomer
formulation comprises one or more fillers in an amount such that
the total amount of filler in the liquid silicone elastomer outer
coat composition corresponds to from about 10 to about 30 percent
by volume of a total volume of the liquid silicone elastomer outer
coat composition.
DETAILED DESCRIPTION
[0007] In the following specification and the claims, which follow,
reference will be made to a number of terms, which shall be defined
to have the following meanings.
[0008] The singular forms "a", "an", and "the" include plural
referents unless the context clearly dictates otherwise. Reference
throughout the specification to "one embodiment" or "an embodiment"
means that a particular feature, structure, or characteristic
described in connection with an embodiment is included in at least
one embodiment of the subject matter disclosed. Thus, the
appearance of the phrases "in one embodiment" or "in an embodiment"
in various places throughout the specification is not necessarily
referring to the same embodiment. Further, the particular features,
structures or characteristics may be combined in any suitable
manner in one or more embodiments.
[0009] "Optional" or "optionally" means that the subsequently
described event or circumstance may or may not occur, and that the
description includes instances where the event occurs and instances
where it does not.
[0010] Approximating language, as used herein throughout the
specification and claims, may be applied to modify any quantitative
representation that could permissibly vary without resulting in a
change in the basic function to which it is related. Accordingly, a
value modified by a term or terms, such as "about" and
"substantially", are not to be limited to the precise value
specified. In at least some instances, the approximating language
may correspond to the precision of an instrument for measuring the
value. Here and throughout the specification and claims, range
limitations may be combined and/or interchanged, such ranges are
identified and include all the sub-ranges contained therein unless
context or language indicates otherwise.
[0011] As noted, the present invention provides methods of
protecting articles having complex shapes from aggressive
environments commonly encountered in human activities such as gas
compression, chemical manufacturing and the like. Applying
protective coatings to articles having a complex shape is
especially challenging when non-line of sight structural features
such as non-linear channels and cavities in surfaces remote from a
visible surface of the articles. For purposes of the present
disclosure, an article having a complex shape is defined as an
article having at least one surface feature requiring protection
and qualifying as a non-line of sight surface feature are present.
A non-line-of-sight surface feature is a surface feature which is
not visible along any possible line of sight and yet is in fluid
communication with the environment.
[0012] It has been discovered that applying, in successive
non-line-of-sight compatible techniques such as dip coating, a low
viscosity silicone bond coat composition followed by a liquid
silicone elastomer outer coat composition having a viscosity
carefully balanced between a high viscosity first liquid silicone
elastomer formulation and a low viscosity second liquid silicone
elastomer formulation affords after curing of the outer coat
composition an article in which substantially all of the
non-line-of-sight surface features have been protected. Those of
ordinary skill in the art will understand that the bond coat may be
cured prior to the application of the liquid silicone elastomer
outer coat composition.
[0013] Articles having complex shapes as defined herein include
centrifugal compressor stator casings; gas turbine compressor
casings; slurry pump impellers; surface pump components; marine
impellers, and drive shafts. In general any system component
requiring protection from an aggressive environment may be suitably
protected using the method disclosed herein.
[0014] In one embodiment, the article to be protected, at times
herein referred to as a first article having a complex shape, is a
compressor component, such as a compressor guide vane. In an
alternate embodiment, the first article having a complex shape is
an impeller.
[0015] Typically, machine components are constructed from metallic
materials such as aluminum and steel and are subject to the
deleterious effects of the environment in which the machine must
operate. In one or more embodiments, the first article having a
complex shape comprises one or more surfaces comprising mild steel,
aluminum, copper, and alloys of the foregoing.
[0016] As noted, the method provided by the present invention
employs a low viscosity silicone bond coat composition which is
applied to essentially all of the external surfaces of the article
to be protected. In one or more embodiments, the performance of the
ultimate bi-layer coating produced may be enhanced by cleaning the
surfaces to be coated with an organic solvent, for example acetone,
prior to the application of the low viscosity silicone bond coat
composition. The silicone bond coat composition is curable and has
a viscosity of less than 1,600 centistokes. In one or more
embodiments, the silicone bond coat composition has a viscosity in
a range from about 500 to about 1,500 centistokes. In one or more
embodiments, the silicone bond coat composition cures at a
temperature in a range from about 80 to about 150.degree. C. and
the cured bond coat has a thickness in a range from about 5 to
about 20 microns.
[0017] The relatively low viscosity of the silicone bond coat
composition facilitates the formation of a thin bond coat layer in
relation to the outer coat layer. Immersion techniques, at times
herein referred to as dip techniques, may be used for articles
having challenging non-line-of-sight surface features. In some
embodiments simple spray techniques may be used to coat
substantially all external surfaces of articles having complex
shapes.
[0018] Suitable silicone bond coat compositions are commercially
available, for example Momentive Silicones' bond coat products
including SS 4044.
[0019] As noted, the bond coat is applied to the article to be
protected and cured at one or more temperatures in a range from
about 80 to about 150.degree. C. to produce an intermediate article
at times herein referred to as the first intermediate article.
Next, a liquid silicone elastomer outer coat composition is applied
using a non-line-of-sight compatible coating technique such as dip
coating or a combination of dip coating and spin coating,
collectively dip coating techniques. In one or more embodiments,
owing to the structure of the article to be coated, the liquid
silicone elastomer outer coat composition may be applied using a
spray technique or a spray and spin technique, collectively spray
techniques.
[0020] The liquid silicone elastomer outer coat composition
comprises a high viscosity, multi-component first liquid silicone
elastomer formulation having a viscosity greater than 300,000
centistokes. The liquid silicone elastomer outer coat composition
also comprises a low viscosity, multi-component second liquid
silicone elastomer formulation having a viscosity less than 6,000
centistokes. The two formulations combine to provide the liquid
silicone elastomer outer coat composition having an appropriate
viscosity when the outer coat composition comprises from about 60
to about 40 percent by weight of the high viscosity first liquid
silicone elastomer formulation and from about 40 to about 60
percent by weight of the low viscosity second liquid silicone
elastomer formulation.
[0021] Suitable high viscosity, multi-component first liquid
silicone elastomer formulations are available commercially and
include Momentive Silicones' LSR2050 product. Suitable low
viscosity, multi-component second liquid silicone elastomer
formulations are available commercially and include Momentive
Silicones' TP3719 product.
[0022] The application of the liquid silicone elastomer outer coat
composition to substantially all external surfaces of the first
intermediate article provides a second intermediate article which
is subsequently heated to one or more temperatures in a range from
about 180 to about 250 degrees centigrade in order to cure the
outer coat composition. Owing to its relatively higher viscosity,
the cured outer layer has a thickness a range from about 50 to
about 500 microns.
[0023] In one or more embodiments, the liquid silicone elastomer
outer coat composition may comprise a filler. Suitable fillers are
known to those of ordinary skill in the art and include
Al.sub.2O.sub.3, graphite, SiO.sub.2, SiC, Si.sub.3N.sub.4, SiCN,
WC, ZrO.sub.2, and combinations of two or more of the foregoing
fillers. In one or more embodiments, the liquid silicone elastomer
outer coat composition comprises about 20 by volume of a filler
based on a total volume of the liquid silicone elastomer outer coat
composition. In one or more embodiments, the filler is
characterized by a maximum particle size in a range from about 2
nanometers to about 10 microns.
[0024] Surface roughness is thought to play a role in the
effectiveness with which the bond coat layer bonds to the liquid
silicone elastomer outer coat composition. In one or more
embodiments, the cured bond coat has a surface roughness in a range
from about 0.5 to about 1 microns and the cured outer coat has a
surface roughness in a range from about 0.5 to about 3 microns.
Experimental Part
[0025] A silicone bond coat composition (SS4044), a high viscosity
first liquid silicone elastomer formulation and a low viscosity
second liquid silicone elastomer formulation (LSR2050 and TP3719)
were obtained from Momentive (Waterford, N.Y.). LSR2050 is a
two-component high viscosity liquid silicone rubber/elastomer
formulation having a nominal viscosity at 20.degree. C. of Pas y=10
s.sup.-1. TP3719 is a two-component low viscosity second liquid
silicone elastomer formulation.
[0026] Viscosity balancing tests were carried out mixing LSR2050
and TP3719 in varying amounts to create the four-component liquid
silicone elastomer outer coat composition having a viscosity
suitable for non-line of sight (NLS) coating of an article having a
complex shape such as an impeller. Suitable viscosities were
achieved when the liquid silicone elastomer outer coat composition
comprised from about 60 to about 40 percent by weight of the high
viscosity first liquid silicone elastomer formulation LSR2050 and
from about 40 to about 60 percent by weight of the low viscosity
second liquid silicone elastomer formulation TP3719. In the
experiments described herein, the liquid silicone elastomer outer
coat composition had a viscosity of about 35,000 centistokes.
[0027] Bi-layer coatings were applied to circular coupons for
corrosion studies and to rectangular coupons for erosion studies.
In order to achieve well adherent coatings, coupon surfaces were
cleaned by sonication in acetone and dried. Cleaned coupons were
dip coated with the SS4044 bond coat composition and bond coat
thickness was maintained between 10-30 .mu.m. The bond coat was
cured in air at 100.degree. C. for 1 h to provide a first
intermediate test article. The four-component liquid silicone
elastomer outer coat composition was prepared by hand mixing equal
amounts LSR2050 and TP3719, and was then applied as a 300-500
micron coat over the bond coat by immersion of the first
intermediate test article (dip process) in the outer coat
composition to provide a second intermediate test article. Fillers,
if present, were added to the four-component liquid silicone
elastomer outer coat composition in an amount corresponding to
about 20 percent by volume of the outer coat composition. The
second intermediate test article was then heated to 200.degree. C.
to cure the outer coat. This curing process in which the outer coat
composition undergoes substantial cross linking was performed with
heating and cooling rates of 3.degree. C./min and a holding time of
1 hr at 200.degree. C. in air.
[0028] Coated test coupons were subjected to a battery of tests to
evaluate coating performance. Scanning microscopy demonstrated good
adhesion of the bond coat to the substrate and a defect free outer
coat strongly bound to the bond coat.
[0029] Coated test coupons exhibited excellent corrosion resistance
relative the uncoated test coupons in 5% NaCl at 25.degree. C. In
an autoclave immersion test at 80.degree. C. and 50 bar with the
test coupon immersed in salt water at pH 3.5, no corrosion of the
test coupons was observed after 720 hours. Unfilled systems as well
as systems comprising Al.sub.2O.sub.3, ZrO.sub.2 or WC fillers all
exhibited excellent corrosion resistance.
[0030] Erosion tests were carried out at room temperature using
sand having an average particle size of 250 microns as the erodent
at a flow rate of 2.5 grams per minute. Erodent angle of approach
was 30 and 90 degrees. Unfilled systems as well as systems
comprising Al.sub.2O.sub.3, ZrO.sub.2 or WC fillers all exhibited
excellent erosion resistance which was about ten times the
resistance of the uncoated test coupon.
[0031] Resistance of the coatings to exposure to hydrocarbons at
high pressure and moderate temperature was demonstrated using a
pressure vessel equipped with a gold plated test coupon holding
cell. In a first test, coated test coupons were exposed to a
mixture of methane (70%) and carbon dioxide (30%) at 10 bar and
80.degree. C. for 100 hours. In a second test, coated test coupons
were immersed in 1% salt solution adjusted to pH 3.5 with
hydrochloric acid in a pressure vessel. The vessel was purged with
a mixture of methane (70%) and carbon dioxide (30%) and then held
at 10 bar and 80.degree. C. for 100 hours. No visible degradation
of the coatings was observed in either test. Filled and unfilled
systems gave similar results.
[0032] Finally, the coated test coupons exhibited good strain
tolerance in a four point bending test. No cracks in the coatings
were observed after being subjected to 3.2% strain.
[0033] The foregoing examples are merely illustrative, serving to
illustrate only some of the features of the invention. The appended
claims are intended to claim the invention as broadly as it has
been conceived and the examples herein presented are illustrative
of selected embodiments from a manifold of all possible
embodiments. Accordingly, it is Applicants' intention that the
appended claims are not to be limited by the choice of examples
utilized to illustrate features of the present invention. As used
in the claims, the word "comprises" and its grammatical variants
logically also subtend and include phrases of varying and differing
extent such as for example, but not limited thereto, "consisting
essentially of" and "consisting of." Where necessary, ranges have
been supplied, those ranges are inclusive of all sub-ranges there
between. It is to be expected that variations in these ranges will
suggest themselves to a practitioner having ordinary skill in the
art and where not already dedicated to the public, those variations
should where possible be construed to be covered by the appended
claims. It is also anticipated that advances in science and
technology will make equivalents and substitutions possible that
are not now contemplated by reason of the imprecision of language
and these variations should also be construed where possible to be
covered by the appended claims.
[0034] This written description uses examples to disclose the
invention, including the preferred embodiments, and also to enable
any person skilled in the art to practice the invention, including
making and using any devices or systems and performing any
incorporated methods. The patentable scope of the invention is
defined by the claims, and may include other examples that occur to
those skilled in the art. Such other examples are intended to be
within the scope of the claims if they have structural elements
that do not differ from the literal language of the claims, or if
they include equivalent structural elements with insubstantial
differences from the literal languages of the claims.
* * * * *